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PRELIMINARY
XRT79L71
506
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
block, to set the FEBE/REI bit, within the very next outbound E3 frame which is destined for the remote
Figure 237 illustrates the Near-End Receive DS3/E3 Framer block receiving an error-free E3 frame. In this
figure, the Receive DS3/E3 Framer block has locally computed an EM byte value of "0x5A" that was computed
over a given incoming E3 frame. Figure 237 indicates that the EM byte value which resides within the very
next incoming E3 frame is of the value "0x5A". As a consequence there is no EM byte errors being detected
as this time.
In response to this un-erred condition, the Transmit DS3/E3 Framer block within the Near-End Terminal will
respond by setting the FEBE/REI bit-field to "0". Figure 238 presents an illustration of the Transmit DS3/E3
Framer block sending this un-erred indicator to the Remote Terminal Equipment.
Next, Figure 239 presents an illustration of a given Near-End Terminal that is detecting an EM byte error,
within its incoming E3 signal. More specifically, the Receive DS3/E3 Framer block has locally computed an EM
byte value of "0x5B" that was computed over a given incoming E3 frame. Figure 239 indicates that the EM
byte value which resides within the very next incoming E3 frame is of the value "0x5A". As a consequence, an
EM byte error is being detected as this time.
FIGURE 237. A SIMPLE ILLUSTRATION OF A NEAR-END TERMINAL EXCHANGING E3 DATA WITH A REMOTE TERMI-
NAL
, IN AN UN-ERRED MANNER
FIGURE 238. A SIMPLE ILLUSTRATION OF THE NEAR-END TERMINAL TRANSMITTING THE UN-ERRED INDICATION TO
THE REMOTE TERMINAL EQUIPMENT
Transmit E3
Framer
Receive E3
Framer
Near-End Terminal
Remote
Terminal
Equipment
Remote
Terminal
Equipment
EM Byte
Locally Calculated
EM Byte
0x5A
Transmit E3
Framer
Receive E3
Framer
Near-End Terminal
Remote
Terminal
Equipment
Remote
Terminal
Equipment
MA Byte
x0xxxxxx
FEBE/REI bit